Mistral released Mistral Large 4 as open weights after three more weeks of reinforcement learning

On October 29, 2026, Mistral AI published the weights of Mistral Large 4 (Le Chonk), an improved version of the October preview. The model was available on Mistral Studio, the Mistral API, OpenRouter, Hugging Face and several clouds.

Archive entry: this covers an event from October 29, 2026, and we published it on November 8, 2026. The details come from sources dated at the time and may have changed since.

On October 29, 2026, Mistral AI published the weights of Mistral Large 4 (Le Chonk), according to the Mistral blog feed. The released model had three weeks of additional reinforcement learning after the October preview.

What changed

Mistral reported 19.7% on FrontierCode 2.0 (Cognition), where it led, and 41% on Terminal-Bench 4.0, up 13 points, with 30% fewer output tokens.
On the AA Coding Agent Index the model scored 48%, effectively tied with GLM-5.3 while using 47% fewer tokens.
Reasoning modes were Low (replacing None), Medium and High (the default).
B3 Agent Security was 97.1%, up from 93.3% in the preview. The model refused 96.6% of malicious cyber requests and scored 51% on the AA Cyber Index.
The API price per million tokens was $0.70 for input, $0.07 for cached input and $2.10 for output.
A cyber variant was in preview for design partners such as Orange Cyberdefense.

Availability and license

The model was available on Mistral Studio, the Mistral API and OpenRouter, and the Hugging Face weights ran with vLLM and SGLang. It was also offered on Vibe Code, NVIDIA-hosted endpoints and NIM, and Microsoft Foundry, the first cloud provider. The license was the Mistral Ecosystem Open-Weight license, a modified MIT license, and Model-as-a-Service businesses needed a separate commercial license.

What it meant for builders

Teams could self-host a 1T-parameter coding and agent model, but companies selling it as a hosted service needed a separate license. The weights were on Hugging Face as mistralai/Mistral-Large-4-1T-A52B, and further sources were Mistral's open-weights announcement and the Hugging Face model page.

Sources

Mistral Blog (Mistral AI, October 29, 2026, official)
Mistral Large 4 (Le Chonk) is now open weight | Mistral (Mistral AI, official)
mistralai/Mistral-Large-4-1T-A52B (Mistral AI, official)

Written with AI assistance, strictly from the sources listed above. Before it went live, automated checks verified its dates, sources and every language edition.